Plant Pest Risk Assessment for Paterson's Curse
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Oregon Department of Agriculture Plant Pest Risk Assessment for Paterson’s Curse, Echium plantagineum 2004 (Revised 2010) Name: Paterson’s curse, salvation Jane, Echium plantagineum Family: Borage, Boraginaceae Findings of This Review and Assessment: Paterson’s curse has been determined to be a category of an “A” listed noxious weed as defined by the Oregon Department of Agriculture (ODA) Noxious Weed Policy and Classification System. This determination is based on a literature review and analysis using two ODA evaluation forms. Using the Noxious Qualitative Weed Risk Assessment v.3.8, Paterson’s curse scored 69 indicating an “A” and a score of 17 with the Noxious Weed Rating System v.3.2. Paterson’s curse is one of the highest ranked weeds due to its drought tolerance, ease of spread and impacts on agriculture. Introduction: Paterson’s curse is a showy ornamental named for the Paterson family of southern Australia who allegedly introduced the plant in the 1800’s as a garden ornamental. Since then, the plant has spread over millions of acres in New South Wales, Western Australia and Victoria provinces. Annual losses for livestock producers are estimated at $30 million annually (Smyth 1999). To some producers it is considered a blessing. Early season growth contains high levels of protein and the species does provide forage during dry years when other forage is limited. Older growth though is far less palatable and competes for water with more valuable grass forage species. In Oregon, Echium p. was first identified in 2003 by an Oregon farmer, at a site one mile north of Lebanon in Linn County. Paterson’s curse infestation in Douglas County in 2004, photo by Ken French, ODA Growth Characteristics: Paterson’s curse is an erect, annual plant, generally 1-3’ tall at maturity. Plants are often multi-branched with an abundance of stout hairs arising from the base. The flower head is curled (scorpioid cyme) and unrolls as the flowers open. Flowers are 5-petaled and blue-purple but many are pink or white. Each flower produces four nutlets surrounded in a 0.5-inch husk covered in bristles giving the plant a fuzzy appearance. Plant Pest Risk Assessment, ODA Echium plantagineum 1 of 11 Paterson’s curse seed head, photo by Tom Forney, ODA Paterson’s curse flowers, photo by Ken French, ODA Nutlets are moderately small and produced in abundance over a long period from spring through late fall as long as insect pollination can occur. Seedling survival is measurably higher in non-native areas compared to native areas. This may account significantly to the overall dominance of Echium in non- native areas (Grigulis 2001) Dispersal is predominantly through agricultural activities and movement of livestock though wildlife may also play a contributing factor. Adaptability to a wide range of environmental conditions is evident in Oregon populations. The species tolerates the wet conditions of the Willamette Valley as well as the drier hillside pastures of Douglas County. Drought tolerance is significant with prolonged flowering and new flushes of seedlings being produced all summer long. Because of its great adaptability and phenotypic plasticity (Sharma and Esler 2008), the potential range of Paterson’s curse is quite large and will expand greatly if no control efforts are employed. Negative Economic Impacts: In Australia, Paterson curse has been labeled either a curse or a salvation. Sheep grazers find that it makes a drought tolerant feed due to high protein levels during the early season. Unfortunately it contains pyrrolizidine alkaloids similar to those found in tansy ragwort causing chronic liver damage when consumed by susceptible livestock (Tazmania 1998). Field and confined feeding trials demonstrate that sheep fed on Paterson’s’ curse put on less weight and produced less wool (Grigulis 2001). Losses do occur mainly from the buildup of copper poisoning in the liver (Seaman 1987). Horses are the most sensitive (Canberra 1999). Pastures, especially those in higher rainfall regions can be completely overrun by Paterson’s curse, reducing yield or becoming a contaminant in hay. Because the seeds last in the soil for 10 years, a higher level of grazing management or chemical controls are needed to eradicate this plant. Because of its limited range in Oregon, economic losses to Paterson’s curse have been limited to control expenses but this would be expected to change if more acreage became infested. Plant Pest Risk Assessment, ODA Echium plantagineum 2 of 11 World Distribution: Paterson’s curse is native to the Mediterranean region and to Western Europe. As a showy and drought tolerant plant, Europeans found it desirable for gardening and sheep forage and have transported it to Australia where it can be found in every state except tropical Queensland. It has spread extensively in South Africa and occupies a variety of habitats there (Sharma and Esler 2008) U.S. Distribution: Outside Oregon, escaped populations have been identified in several other states including New York, California, Massachusetts and Pennsylvania (USDA Plants database). US distribution of Paterson’s curse on USDA Plant Database Oregon’s distribution of Paterson’s curse on WeedMapper.org Plant Pest Risk Assessment, ODA Echium plantagineum 3 of 11 Positive Economic Impacts: Beekeepers praise the plant for its capacity to produce a surplus of clear honey (Harrison 2005). Australian beekeepers have access to vast acreages of Paterson’s curse and can harvest larger surpluses for sale. Vegan and health food advocates tout the lipid reducing capacity of Echium oil when used as a dietary supplement. Echium oil is rich in Omega-3 and Omega-6 fatty acids as serves as a replacement for fish oil (Mir 2008). Europe is the leader in commercial Echium oil production. Echium plantagineum is also marketed as an ornamental in the gardening trade under the name “Dwarf Blue Bedder” (Michigan 1999). Environmental Impacts: The greatest environmental impacts could be expected to come from reductions in species diversity and natural forage production in seasonally dry land environments. It is not clear if it would invade Northern Great Basin rangelands. Control: Grazing and mowing can reduce plant size but seed production often is unaffected due to late season regrowth (Grigulis et. al. 2001). Mowed plants regrow and set seed even in very dry soils. Several growth regulator type herbicides are effective at controlling seedlings and rosettes though later season growth is very resistant to herbicide effects. In rangeland, control costs can often exceed the value of the forage produced. Plant Pest Risk Assessment, ODA Echium plantagineum 4 of 11 Noxious Weed Qualitative Risk Assessment Oregon Department of Agriculture Common name: Paterson’s curse Scientific name: Echium plantagineum Family: Borage, Boraginaceae For use with plant species that occur or may occur in Oregon to determine their potential to become serious noxious weeds. For each of the following categories, select the number that best applies. Numerical values are weighted to increase priority categories over less important ones. Choose the best number that applies, intermediate scores can be used. Total Score: 69 Risk Category: A GEOGRAPHICAL INFORMATION 1) 6 Invasive in Other Areas 0 Low- not known to be invasive elsewhere. 2 Known to be invasive in climates dissimilar to Oregon’s current climates. 6 Known to be invasive in geographically similar areas. Comments: Highly invasive in Australia, South Africa. 2) 6 Habitat Availability: Are there susceptible habitats for this species and how common or widespread are they in Oregon? 1 Low – Habitat is very limited, usually restricted to a small watershed or part of a watershed (e.g., tree fern in southern Curry County). 3 Medium – Habitat encompasses 1/4 or less of Oregon (e.g., oak woodlands, coastal dunes, eastern Oregon wetlands, Columbia Gorge). 6 High – Habitat covers large regions or multiple counties, or is limited to a few locations of high economic or ecological value (e.g., threatened and endangered species habitat). Comments: Highly adaptable to a variety of climates. 3) 0 Proximity to Oregon: What is the current distribution of the species? 0 Present – Occurs within Oregon. 1 Distant – Occurs only in distant US regions or foreign countries. 3 Regional – Occurs in Western regions of US but not adjacent to Oregon border. 6 Adjacent – Weedy populations occur adjacent (<50 miles) to Oregon border. Comments: Found in two populations in Oregon. 4) 10 Current Distribution: What is the current distribution of escaped populations in Oregon? 0 Not present – Not known to occur in Oregon. 1 Widespread – Throughout much of Oregon (e.g., cheatgrass). 5 Regional – Abundant (i.e., occurs in eastern, western, central, coastal, areas of Oregon) (e.g., gorse, tansy ragwort). 10 Limited – Limited to one or a few infestations in state (e.g., kudzu). Comments: Limited to two populations in state. Plant Pest Risk Assessment, ODA Echium plantagineum 5 of 11 BIOLOGICAL INFORMATION 5) 4 Environmental Factors: Do abiotic (non-living) factors in the environment effect establishment and spread of the species? (e.g., precipitation, drought, temperature, nutrient availability, soil type, slope, aspect, soil moisture, standing or moving water). 1 Low – Severely confined by abiotic factors. 2 Medium – Moderately confined by environmental factors 4 High – Highly adapted to a variety of environmental conditions (e.g., tansy ragwort, Scotch broom). Comments: Highly adapted to a wide range of conditions. 6) 5 Reproductive Traits: How does this species reproduce? Traits that may allow rapid population increase both on and off site. 0 Negligible – Not self-fertile, or is dioecious and opposite sex not present. 1 Low – Reproduction is only by seed, produces few seeds, or seed viability and longevity are low. 3 Medium – Reproduction is vegetative (e.g., by root fragments, rhizomes, bulbs, stolons). 3 Medium – Produces many seeds, and/or seeds of short longevity (< 5 years).